1.vacabulary

dumb adj 啞的，笨的。

irresponsible adj. 不負責任的，不可靠的

eg It seems you've been a bit irresponsible.

2.phrase

save for

eg save it for the Ethics Committee.

3.useful sentences

1）Don't play dumb with me

=別跟我裝傻，別和我裝蒜，別裝糊涂，

=別想裝傻糊弄我

=Don't play dumb.

假裝頭腦遲鈍或者缺乏某種好處。

play dead裝死